PROJECT SUMMARY/ABSTRACT: DEVELOPMENTAL CORE Humans are frequently exposed to low levels of potentially hazardous chemicals in the environment, diet, water, medicines, and through occupational exposures. Many of these compounds or their reactive metabolites can bind to macromolecules and exert toxic effects leading to neurotoxicity, endocrine disorders, cardiovascular and other diseases. Other chemicals can induce mutations leading to the development of cancer. Over the past 30 years gas chromatography/mass spectrometry (GC/MS) and more recently liquid chromatography/mass spectrometry (LC/MS) have been employed to measure exposures to certain classes of chemicals. These measurements have been largely restricted to monitoring a single or up to several chemicals within a common class of toxicants. There is a critical unmet need to develop analytical methods to comprehensively measure for a wide range of environmental and dietary chemicals that contribute to human diseases. With the emergence of triple quadrupole, ion trap, and high resolution accurate mass spectrometry (HRAMS) instruments, it is now possible to screen for multiple classes of toxicants in the environment and diet in a single assay to capture the totality of the toxicant exposome. Tandem MS instruments can also measure multiple biomarkers of effects of toxicants, such as oxidative stress markers and DNA adducts. Moreover, the same technologies can measure a wide panel of phytochemicals and nutrients in the diet that can protect against diseases. We propose to develop comprehensive analytical approaches to measure a wide range of environmental and dietary toxicants, as well as endogenous markers of oxidative stress, and nutrients and phytochemicals that are essential for nutrition and growth. We will employ multistage MSn and HRAMS scanning techniques to maximize the number of chemicals and biomarkers that can measured in a single assay using different biopsecimens. In Aim 1, we will develop methods to measure pesticides, chemicals in packaging materials, per- sistent polyfluorinated toxicants, and selected carcinogens using urine and plasma, and we will employ hair as a biospecimen to screen for longer-lived biomarkers of these toxicants. In Aim 2, we well develop assays to mea- sure for multiple phenolic antioxidants in the diet by measuring their uptake and bioavailability in plasma and urine. In Aim 3, we will characterize endogenous biomarkers of oxidative stress in urine, plasma, and we will em- ploy hair and toenails to measure long-term exposure to these biomarkers. In Aim 4, we will examine saliva for reactive volatile aldehydes formed in tobacco smoke and e-cigarettes and measure their DNA damage in the oral cavity. Formalin fixed paraffin embedded tissues, an untapped biospecimen to measure DNA damage, will be used to screen DNA adducts of genotoxicants in tobacco and meats. The successful development of methods to measure these chemicals and biomarkers in multiple biospecimens will greatly expand the number of analytes that the HHEAR can provide to collaborators who seek to understand health effects and risks of chemicals.